Proxy URL's URI is being stripped off

### Subject of the issue
Proxy URL's URI is stripping off
I have a Proxy URL as https://mydatapower.com/proxy/direct, which directs to https://ims-na1.adobelogin.com"
"/proxy/direct" is being stripped off, but this is required for our proxy to recognize the request.

### Your environment
QA

### Steps to reproduce
1. in OAuth2IMSTokenProviderTest.java replace TEST_ENDPOINT with "https://mydatapower.com/proxy/direct"
2. Log the endpoint in OAuth2IMSTokenProvider.java ; the output is "https://mydatapower.com/ims/token/v3"

### Expected behaviour
3. From our proxy point of view , the url should be "https://mydatapower.com/proxy/direct/ims/token/v3"

### Actual behaviour
the output is "https://mydatapower.com/ims/token/v3"

Start with OAuth2IMSTokenProviderTest.java and OAuth2IMSTokenProvider.java, using the TEST_ENDPOINT reproduction and logged endpoint as the entry point. Trace how the proxy URL is combined with the token path. Done means the endpoint retains /proxy/direct and produces https://mydatapower.com/proxy/direct/ims/token/v3.

Written by the indexing model from the issue text.